Friesea eureka, Greenslade, 2018

Greenslade, Penelope, 2018, A new species of Friesea (Collembola: Neanuridae) from the Antarctic Continent, Journal of Natural History 52 (33 - 34), pp. 2197-2207 : 2199-2204

Genus Friesea Dalla Torre, 1895

Friesea eureka sp. nov.

( Figures 1–3 )

Type locality

Tereshkovoi Oasis , near Molodyezhnaya Station , Enderby Land, Eastern Antarctica, 67.66527778S, 45.8338333E, leg V . Bulavintsev , 6 .i .1989, ( SAMA).

Material examined

Holotype: Male, slide D. East Antarctica, Tereshkovoi Oasis , 6 January 1989, V. Bulavintsev (2 coverslips) . Paratypes: Same data as holotype (2 coverslips), nspecimens mainly immatures (All SAMA).

Other material: Slide A Molodyezhnaya Station, January 1989, V . Bulavintsev ; Slide B East Antarctica, Tereshkovoi Oasis, 6 January 1989, V . Bulavintsev; Slide C. East Antarctica, Tereshkovoi Oasis, 6 January 1989, V . Bulavintsev (2 coverslips), 10 specimens on this slide, one male is holotype, other 9 including female are paratypes. All material deposited in the South Australian Museum .

Description

Colour. Pale grey on slides.

Habitus. Small, elongate specimens.

Length. 0.72 to 0.96 mm (n = 10).

Ratio. Head length (lateral):antennal length:body length = 1.8:1:5. Chaetotaxy and cuticle. Most specimens received were juveniles with a reduced and asymmetric chaeotaxy. Chaetal asymmetries present mid-dorsally. Even in adults, chaetotaxy is not stable. For instance, one male has a pair of deeply bifurcate p1 on abd V. All Mc and me chaetae are smooth and pointed, becoming longer posteriorly. Mc chaetae stoutish. S chaetae very fine, thin, not particularly long relative to segment length. Broad S chaetae on antennal segment III (2) and IV (6). Number and arrangement of S chaetae as for genus but because of losses and asymmetries of some chaetae, position not always clear. For instance, S chaeta appears in position of m2 on abd V and not m3 as m2 is absent.

Head and antennae. Antennal segments III and IV partially fused dorsally; ant I with 7 chaetae, no mi seen; ant II with 11 chaetae; ant III organ with 2 broad clubs in cuticular groove, 1 very long, curved S chaeta dorsally and 1 ventrally; ant III with 16 chaetae with 3 mi ventrally; 6 thick curved S chaetae on ant IV, no others distinct, S1 thinner than others; S7 and 8 thicker; less developed in some individuals; apical bulb on ant IV conspicuous and single; organite and mi present. Antennal IV ventrally with small sensorial rasp consisting of about 9–10 short, bluntish chaetae; L chaeta present on labium but seta A or B absent in juveniles and D displaced laterally also in juveniles, sometimes asymmetrically present; labrum with 5, 4, 4 chaetae from posterior to anterior, most posterior central ao chaeta longer than adjacent chaetae; ocelli 4 + 4 lenses, plus 1 + 1 reduced and hardly visible, but six pigmented eye spots on head; 3 interocular chaetae; head with chaetae Do present, p1, p2, c1, c2 present; v1, v2 absent; ventral head with 2 + 2 chaetae.

Ratio. Antennal segments: I:II:III = 1:1.5:1.5.1.6.

Thorax and legs. Dorsal chaetotaxy of thorax and legs as in Tables 1 & 2 and Figures 1i , 2a,b,c respectively. No ventral thoracic chaetae; number of tenent hairs up to 5 in adults, variable and only lightly clavate; claw moderately narrow, lacking teeth ( Table 2 and Figure 2b,c ). Internal length of claw and anal spines at m1 variable with maturity, sometimes approximately equal in length varying from: 1:1.5 to 1:1.1.

Abdomen and appendages. Ventral tube with 3 + 3 (4 + 4) chaetae in adult ( Figure 2d ); two minute teeth on the remnant of retinaculum; manubrium with 8 + 8 chaetae; dens reduced, with 3 + 3 mi and slight indication of mucro as minute pimple ( Figure 2g,h ); anal lobes with 12 (11) chaetae, macrochaetae not always seen; m1 missing on abd IV; S chaetae thin, pointed, longish on abd; on abd IV S chaeta at p4; at p3 on abd V but p2 absent; nearly as long as Mc on abd V and three-quarters as long as segment ( Figure 2e,f ); abd VI a1 longer than on abd V in female. Abd VI with 2 + 2 spines in adult and macrochaetae longer, thick and spine-like; on Abd VI po is unpaired, m1 as a slightly curved long thick spine, a1 with shorter straight spine; a2 long spinose chaeta; m2 long, spinose chaeta; po on abd VI as short fine chaeta ( Figure 3a,b ). Progression of spinal development: m1 to a1 to a2 (long) to m2. Spines not fully

are indicated by brackets.

developed in immatures, with abd VI becoming longer with greater spine development in adult. Ventral chaetotaxy: abd II 5 + 5, abd III 7 + 7, abd IV 3 + 3 ( Figure 3f ).

Abd V ratios length of segment: Mc:me:s = 2:1.8:1:1.5. abd v S 22, Mc p122, me a1 13. Abd VI ratios length of anal spines on abd VI: a1:a2:m1:m2 = 2:1:1:2.4

Abd VI ratios claw: me:a1 spine: m1 spines, M p2 = 1:1: 1.3: 1.8: 2.6.

Abd VI ratios claw: po = 2.5:1.

Genital apertures. Male with 18 circum-aperture chaetae, 4 + 4 internal strong chaetae on in sexual phase. Female with 10 chaetae, 3 + 3 mi internally ( Figure 3d,f ).

Diagnosis

This species differs from all other Friesea species on the Antarctic continent in having 4 + 4 ocelli + 1 + 1 regressed, a small sensorial rasp ventrally on ant IV, 4 straight spines on abdomen VI not inserted into papillae, 2 + 2 spine-like chaetae on abd. VI and S chaetae long, nearly as long as Mc on abd V.

Biology

Several specimens had tardigrade claws and rotifer trophi (mouthparts) in their alimentary canals. The genus has been known to feed in micro-invertebrates since Cassagnau’ s (1958) publication. Ten species of Tardigrada are known from aquatic habitats near Molodyezhnaya Station and at the Tereshkovoi oasis ( Opaliński 1972; Tsujimoto et al. 2014). The rotifer fauna has also been described.

Figures

Figure 1. Friesea eureka sp. nov. (a) Right side of dorsal head chaetotaxy; (b) enlargement of ocellus patch and chaetae on left side of head; (c) lateral view of mandible; (d) lateral view of maxilla; (e) labrum; (f) labium and ventral head chaetotaxy; (g) ventral antennal segments; (h) dorsal antennal IV chaetotaxy, ordinary chaetae indicated by open circles; (i), dorsal chaetotaxy of thorax I, II.

Figure 2. Friesea eureka sp. nov. (a) Leg III coxa, trochanter and femur; (b) ventral chaetotaxy of tibiotarsus III; (c) dorsal chaetotaxy of tibiotarsus III; (d) ventral tube; (e) chaetotaxy of abdominal segments I and II; (f), chaetotaxy of abdomen III and IV; (g) furcal region lateral view; (h) ventral chaetotaxy of abdomen III showing furca and manubrial chaetae; (i) dorsal chaetotaxy of abdomen V.

Figure 3. Friesea eureka sp. nov. (a) Dorsal chaetotaxy of abdomen VI showing spines and spine-like chaetae; (b) lateral view abdomen V, VI; (c) anal lobes; (d) female genital opening; (e) male genital opening; (f) ventral chaetotaxy abdomen I to III.